Vehicle control system for internal combustion engine

Abstract

A vehicle control system for an internal combustion engine having a fuel injection valve for injecting fuel directly into a combustion chamber includes a controller configured to perform a fuel cut-off when a predetermined fuel cut-off condition is met during travel of the vehicle to thereby stop fuel injection from the fuel injection valve. The controller is configured to resume the fuel injection from the fuel injection valve when a predetermined fuel cut-off recovery condition is met during the fuel cut-off. The controller is configured, upon elapse of a predetermined time that is required for a wall temperature of the combustion chamber to rise after resuming the fuel injection from the fuel injection valve, to perform a rich spike that temporarily increases the fuel injection amount from the fuel injection valve.

The invention claimed is: 
     
       1. A vehicle control system for an internal combustion engine having a fuel injection valve for injecting fuel directly into a combustion chamber, comprising:
 a controller configured to perform a fuel cut-off when a predetermined fuel cut-off condition is met during travel of the vehicle to thereby stop fuel injection from the fuel injection valve, and 
 wherein the controller is configured to resume the fuel injection from the fuel injection valve when a predetermined fuel cut-off recovery condition is met during the fuel cut-off, and 
 wherein the controller is configured, upon elapse of a predetermined time that is required for a wall temperature of the combustion chamber to rise after resuming the fuel injection from the fuel injection valve, to perform a rich spike that temporarily increases the fuel injection amount from the fuel injection valve. 
 
     
     
       2. The vehicle control system according to  claim 1 , wherein, as a fuel cut-off period is longer, the predetermined time is configured to be longer. 
     
     
       3. The vehicle control system according to  claim 1 , wherein, as a wall temperature of the combustion chamber is lower, the predetermined time is configured to be longer. 
     
     
       4. The vehicle control system according to  claim 1 , wherein, during a period between when the fuel cut-off ends and when the predetermined time has elapsed, the ignition timing is configured to be advanced. 
     
     
       5. The vehicle control system according to  claim 4 , wherein, as the fuel cut-off period is longer, the ignition timing advance amount is configured to be larger. 
     
     
       6. The vehicle control system according to  claim 4 , when the internal combustion engine is in a high-load operating state, the ignition timing is prohibited from being advanced from the fuel cut-off termination until elapse of the predetermined time. 
     
     
       7. A vehicle control system for an internal combustion engine having a fuel injection valve for injecting fuel directly into a combustion chamber, comprising:
 a controller configured to perform a fuel cut-off when a predetermined fuel cut-off condition is met during traveling of the vehicle to stop fuel injection from the fuel injection valve, 
 wherein the controller is configured to resume the fuel injection from the fuel injection valve when a predetermined fuel cut-off recovery condition is met during the fuel cut-off, 
 wherein the controller is configured, upon elapse of a predetermined time after resuming the fuel injection from the fuel injection valve, to perform a rich spike operation that temporarily increases the fuel injection amount from the fuel injection valve, and 
 wherein, as a fuel cut-off period is longer, the predetermined time is configured to be longer.